High pressure switch



Oct. 7, 1941. J. RUSSELL HIGH PRESSURE SWITCH Filed Feb. '7, 1940 2 Sheets-Sheet l WW h momii 1941- J. RUSSELL 2,257,816

HIGH PRESSURE SWITCH pram-0&

ORNEYS Patented Oct. 7, 1941 HIGH PRESSURE SWITCH John Russell, Danbury, 001111., assignor to Pressurelube, Inc., Dover, Del., a corporation of Delaware Application February 7, 1940, Serial No. 317,673 6 Claims. (01. 20082) The present invention relates to new and useful improvements in pressure operated switches.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious hereirom, or may be learned by prac tice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure l is a front elevation partly in section and with the cover partly broken away;

Figure 2 is a plan view partly in section;

Figure 3 is a vertical section taken on the line 3-3 of Figure 1;

Figure 4 is a front elevation on a smaller scale than Fig. 1 and showing the pressure setting dial;

Figure 5 is a vertical section similar to Figure 3 but showing a modification;

Figure 6 is a vertical section taken on the line li-Bof Figure 5; and

Figure '7 is a front elevation of detail of construetion.

Referring now in detail to the drawings there is illustratively shown a channel shaped housing I0 having end flanges or Walls l2, l3 and adapted to support within and upon it the operable parts of a switch for operation at extremely high pressures. A strap-like member H is secured, as by welding, in recesses formed in the front edges of the walls l2 and I3 and is provided with outwardly projecting, apertured ears M by means of which the device may be mounted upon apparatus with which it may be associated. A cover plate l5, also channel shaped, may be provided to completely enclose the mechanism contained within the housing [0 and may be secured in position by screws l6 which are threaded into the strap member ll.

Slidably mounted in the end walls [2, l3 of the housing In near the upper edges thereof and in parallel spaced relation to each other are a pair of contact bearing slide rods l1, l8, each of these rods carrying similarly constructed contact plates so positioned upon the rods that their contact buttons are in opposed relation to each other.

As embodied, the contact plate 2|, carried by the slide rod Il, may be generally oval in shape and consist of insulating material such as Bakelite, hard rubber, fiber or similar substance. A hub 22, secured in an aperture near one end of the oval contact plate 2|, serves as means for adjustably mounting the contact plate upon the rod I1 and a set screw 23 permits the fixing of the plate in any desired position. The end of the contact plate 2| opposite the hub 22 may be forked so as to span the rod |8 and be guided thereby to maintain its proper alinement. The upper central portion of the contact plate is provided with a metallic contact button 24, which may be secured to the plate by a rivet 25, and to one end of this rivet may be attached, as by soldering, one end of a flexible and insulated lead wire 26 the other end of which may be secured to a terminal post 21 mounted in but insulated from the end wall l3 of the housing I0.

A second contact plate 39, similar to plate 2|, is adjustably mounted on the slide rod l8 by means-of its hub 3| and set screw 32, and its metallic contact button 33 is connected by a lead wire 34 to a terminal post 35 mounted in but insulated from the end wall |3 of the housing I0 conveniently near the terminal post 21. The contact plate 30 and its contact button 33 is maintained in operative alinement with plate 2| and button 24' by being forked atone end so as to span and be guided by the rod [1.

For maintaining the two contact buttons 24, 33 in electrical contact with each other, except under conditions to be described later, there is provided a compression spring 36 mounted upon the slide rod I8 between the end wall l3 and the hub 3| of contact plate 3|! so as to always urge the plate 30 towards the contact plate 2|. Thus, the electrical switch formed by the two contact buttons 24, 33 remains normally closed to form a complete circuit from terminal post 21 to terminal post 35 until such time as slide rod [8 may be moved to the right (Fig. 2) to break such circuit.

Means for breaking the electrical circuit through the contact buttons 24, 33 by utilization of high fluid pressure are provided and. as embodied consist of a pressure chamber 40, formed in the outer end of a block 4| mounted in the end wall l2 of the housing It], and a pressure actuated plunger 42 slidably mounted within the block ll and projecting into the chamber 40. A pipe 43 connects the chamber to any source of extremely high fluid pressure it may be desired to utilize for the purpose of actuating the switch and a spring-pressed packing gland 44 serves to seal the opposite end of the chamber 40, through which the plunger 42 projects, against leakage. The inner end 45 of .the plunger 42 is enlarged and slidably supported in a bore 46, formed in the inner end of the block 4|, from which it projects into the interior of the housing I0. A spring seat 4'! is fixed upon the end of the enlarged portion 45 of plunger 42 so as to form an abutment for one end of a compression spring 48 the other end of which abuts and is affixed to the end wall I3, as by a screw held clip 49. The spring 48 forms the reactance for the fluid pressure to be utilized for opening the switch as this pressure is applied to the end of plunger- 42 in pressure chamber 40, and the pressures used may vary from a few thousand to ten, fifteen or more thousand pounds per square inch.

Means for transmitting the movement of the plunger 42, as pressure is applied thereto, to the slide rod i3 and thus break the contact between the two contact buttons 24, 33, are provided. As embodied they comprise an upwardly. extending, offset 'arm50, the upper end of'which is forked so as to embrace the slide rod l8 near its journal in the end wall I2, and a collar 5| slidably mounted upon the rod I8 and adapted to be fixed at any predetermined position in the path of movement of the arm 50 by a set screw 52. Thus it will be seen that as fluid pressure is admitted into chamber 40 in excess of the strength of the spring 48.,the plunger 42 will moveto the right (Fig. 1) and'eventually bring the arm 50 into contact with the collar 5i on slide rod I8. Continued movement of the plunger 42 thereby moves with it the slide rod [8, compressing the spring 36 on said rod and moving the contactbutton 33 away from contact button 24, thus breaking the electrical circuit. .As pressure decreases in the chamber .00, the reactance spring 48 moves the arm 50 and plunger 42 to the left and spring 36 causes slide rodIB and contact button 33 to follow this movement until the two contact buttons again meet to complete the electrical circuit. Further decrease of pressure merely moves the arm 50 away from collar 5| until reactance spring 48 reaches zero compression.

Means are incorporated within the device whereby an operator may, conveniently and from the outside of the device, predetermine the relation between the actuating fluid pressure and the point at which this pressure will break the electrical circuit. .As embodied, there is provided on the slide rod I! a U-shaped stop clamp 60 having a set screw BI to fix its position on the rod I! and an upstanding finger 62 to which one end of a tension spring E3is secured. The other end of the spring 63 is fixed to the wall I2 of the housing I and the spring lies parallel to the rod I1. ()ne arm .64 of the stop clamp 60 is longer than the other and liesin the path of a detent finger which is rigidly attached to a collar 06 pinned to a shaft 01. The shaft 6! is journalled in the rear wall of the housing I0 and projects forwardly through a journal in the strap II and cover I5. A dial knob 58 having the usual pointer thereon is secured to the end of shaft 61. by a set screw 69 and a calibrated dial may be affixed on the-cover I5 in cooperative relation to the dial knob 68. The calibrations on the dial I0 may be in any desired units of pressure within the range of pressures for which the device is to be used.

Frictional means are provided for maintaining the shaft 61 and detent finger 65 in whichever position the operator may select and as embodied comprise a reasonably strong compression spring 12 encircling the shaft 61 and abutting the rear face of the strap II and the forward face of the collar 56 thus forcing the rear face of the collar 66 into strong frictional engagement with the rear wall of the housing 10. Limiting stops 13, I4, set into the rear wall of the housing I0 in the path of movement of the detent 65 serve to prevent rotating the pressure selecting shaft 61 beyond its effective range of movement. It will thus be seen that the stop clamp 60 on the slide rod IT is always held against the detent 65 by the spring 63, and the position of the contact buttons 24, 33 relative to the pressure actuated arm 50 is determined by the position of the detent 65 as set by the dial knob 68, this setting being variable at the will of the operator to which ever pressure he may select within the range of the device.

Thus a clockwise rotation of dial knob 68 will move'the contact buttons to the right (Fig. 2) and increase the distance between the pressure actuated arm 50 and the collar 5| carried on the slide rod I8, necessitating a greater fluid pressure to break contact between buttons 24 and 33. A counter-clockwise rotation of knob 68 so sets the contact buttons as to require less pressure to break their contact.

Referring now to Figs. 5, 6 and 7, there is shown a modified form of means whereby the circuit breaking positions of the contact buttons 24, 33 relative to the pressure actuated arm 50 may be varied within a limited pressure range, and simple, adjustable means associated therewith whereby the said pressure range of the switch may also be maintained for example, from a range of four to fifteen thousand pounds per square inch regardless of minor irregularities in the strength of the main spring 48. The mechanism by which the pressure range may be maintained utilizes the same limited rotation of a dial knob for all strengths of springs within the manufacturing tolerances of the spring thereby insuring accuracy of the pressure range of the switch and making the graduations on the knob equally accurate.

However, the range may also be varied with any spring so as to vary the working range of the switch, thereby enabling it to operate at four to twelve thousand or from four to twenty thousand pounds per square inch, for example. Thus, on the dial knob the center mark may represent a circuit breaking pressure of 12,500 pounds in a pressure range of 10 to thousand pounds per square inch, but the same mark in a pressure range of 10 to thousand pounds represents a circuit breaking pressure of 20,000 pounds.

As embodied, in the modification, there is provided on the slide rod IT a rectangular stop plate I00 to which is secured one end of the tension spring 63. A set screw IOI, provided in the hub of stop plate I00, serves to adjustably position the plate on the rod I I. One side of thestop plate I00 lies in the path of a detent finger I02 whose base I03 is attached to a friction disc I04 which is pinned or otherwise secured on the dial knob shaft 61 adjacent the rear wall of the housing l0, but spaced therefrom by a friction washer I05. A notch I06, provided in the periphery of the disc I04, cooperates with a stop pin I07 to limit the rotation of the disc, the limits of this rotation representing the high or low pressure in the pressure range at which the switch may be set to break the circuit. The friction necessary to maintain the disc Hi4 in its set position is provided by the compression spring 12, previously described. A dial knob I93 is secured on the outer end of shaft 60 and provided with graduations (not shown) on a portion of its periphery and adapted to be read against a pointer I99 attached to the cover It at a convenient spot.

It will thus be seen that a partial rotation of the dial knob 33 will cause the detent N12 to act upon stop plate H and move it to the right or left, as the case may be, to vary the position of the contact buttons 2t, 33, relative to pressure actuated arm 50.

It is desirable that the pressure range of the device may be altered without changing the limit of rotation provided for the dial knob I98 by the pin HF and for this purpose the detent I02 may be made of a material, such as soft iron or steel, adapted to be bent toward or away from the center of rotation of the disc I04. By this expedient it will be noted that the same limited rotation of disc I04 produces lineal movements of the stop plate lull which may be greater or less as the detent I02 is further from or nearer the center of disc rotation. Thus, if detent 882 is bent toward the disc center, as shown in dot and dash lines in Fig. 7, a rotation of the disc Hi4 through its limit of motion will produce a smaller circumferential movement of the detent tip than the same rotation of the disc will produce if the detent is bent to its outermost position, as indicated in solid lines in Figure '7.

When the device is connected in a fluid pressure system, such as a high pressure lubricating grease dispensing apparatus, in which the pres sure is created by an electric motor controlled by the switch contained within the device, it will be seen that, when the pressure reaches a preselected point the electrical circuit to the motor is broken and the motor stops after the exhaustion of its momentum has created a slight increase of pressure over that required to break the circuit. After this slight excess pressure has been used in the ordinary course of operation the drop in pressure in the chamber 4!! permits the switch to close and thus again start the motor to supply more pressure. The device thus operates to provide a constant supply of grease under a pre-selected pressure and to maintain this pressure within narrow limits. It also permits by means of its convenient dial knob 68 and direct reading dial 10 a quick and easy method of changing, during operation, the pressure at which the device will operate.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is: g

1. A pressure operated switch for extremely high pressure operation including in combination a high pressure piston, a spring opposing movement of the piston, a pair of relatively movable contacts, a pair of rods carrying the contacts, a casing in which the rods are individually slidable, spring means for relatively moving the contacts and means interconnecting the piston with one of the rods, and means for variably positioning the other rod and its contact to vary the pressure required for operation of the switch.

2.A pressure operated switch for extremely high pressure operation including in combination a high pressure piston, a spring opposing movement of the piston, a pair of relatively movable contacts, a pair of relatively movable rods on which the contacts are individually mounted, a spring moving the contacts relatively towards each other, a frictionally held arm for variably positioning and holding one rod and its contact, and a stop carried by the other rod and engageable with a loosely fitted member moved by the piston for moving the rod and its contact when a predetermined pressure is exerted on the piston.

3. A pressure operated switch for extremely high pressure operation including in combination a casing, a high pressure piston supported at one end of the casing, a spring compressed between the piston and the other end of the casing, a pair of parallel rods supported by the casing and slidable therein, coacting contacts carried by the rods and closed by relative movement of the rods, a dial frictionally held against rotation, an arm connected to the dial for moving one of the rods and its contact to vary the pressure at which the switch is actuated, a spring for relatively moving the rods and a lost motion connection between the piston and the other rod for actuating the switch by excessive pressure on the piston.

4. A pressure operated switch for extremely high pressure operation including in combination a casing, a high pressure piston sup-ported at one end of the casing, a spring compressed between the piston and the other end of the casing, a pair of parallel rods supported by the casing, a pair of relatively movable contacts carried by the rods, frictionally held movable means for moving one of the contacts to vary the pressure at which the switch opens, a spring for moving the other contact to closing position and an arm having lost motion relative to the spring-moved contact and moved by the piston on excessive pressure for moving the contacts relatively apart.

5. In a high pressure switch a high pressure piston to be operated by fluid pressure, a spring compressed by the piston, a pair of relatively movable contacts, one of which is moved by the piston, a rotary adjusting member, a plate carried by and moving the other contact and adjacent to the axis of the rotary member, and a radially movable finger on the rotary member engageable with the plate to vary the normal position of the second contact.

6. A pressure operated switch for extremely high pressure operation including in combination a high pressure piston, a spring opposing movement of the piston, a pair of relatively movable contacts, a pair of rods carrying the contacts, a casing in which the rods are individually slidable, spring means for relatively moving the contacts and means interconnecting the piston with one of the rods, means for variably positioning the other rod and its contact to vary the pressure required for operation of the switch, and means for varying the relation of the last means and the other rod to vary the normal setting of the switch.

JOHN RUSSELL. 

